In diagnosing diabetes, be it type 1 or type 2, one of the key factors doctors look for is C-peptide levels. Traditionally, scientists have believed that low C-peptide levels indicated type 1 diabetes as the body is unable to produce an adequate supply (if any) of insulin, while higher C-peptide levels were associated with type 2 diabetes as the body made insulin but was unable to effectively use it.

However, a recent study shows that this may not be entirely accurate. In a large cohort study in Scotland, there was a broad range of variability in C-peptide persistence across individuals of different ages and duration of disease. Individuals who were older when diagnosed and were close to age of diagnosis had higher C-peptide levels than those who were adolescents when diagnosed and had been living with the disease for a longer period of time. Scientists believe this may point toward there being multiple genetic networks that impact diabetes risk.

The findings also showed that similar C-peptide levels may be present in individuals with adult-onset type 1 diabetes who did not immediately require insulin treatment as those who were diagnosed with type 2 diabetes. Many people with higher C-peptide levels also have increased amounts of proinsulin, which is a prohormone precursor to insulin. However, the cells do not respond to primary stimuli which could mean that they are in a stunned state. If this is the case, there is a potential that they could recover and once again play an active role in insulin production.

The ratio of proinsulin to C-peptide may also be influenced by genetic risk of diabetes. Both genetics and environmental factors may come into play regarding damage to beta cells and their ability or inability to produce insulin.

This study challenges previous understanding about the differences in type 1 and type 2 diabetes when it comes to diagnosis and treatment. There may be the potential to stimulate pancreatic beta cell function in individuals with type 1 diabetes depending on their levels of proinsulin, insulin, and C-peptide.

Diabetes Research Connection (DRC) is interested to see how this may impact the future of diagnosis and treatment of diabetes. It could certainly lead the way to more in-depth research opportunities, and the DRC provides critical funding to support these types of initiatives. Early career scientists can receive up to $75K from the DRC to pursue novel research projects focused on type 1 diabetes. To learn more, visit https://diabetesresearchconnection.org.